The objectives of this research are: 1. To establish a library of hybridoma cell lines producing monoclonal antibodies which recognize specific outer membrane antigens of Vibrio cholerae. These experiments will be directed toward the isolateion of potential monoclonal antibodies to virulence associated outer membrane antigens (lipopolysaccharides, iron-transport proteins, hemagglutinin/protease proteins and others) which are expressed on the cell surface of organisms grown in vivo in the infant rabbit model of cholera disease. 2. To investigate the function of individual outer membrane proteins and to determine if monoclonal antibody to specified outer membrane antigens are protective against Vibrio cholerae colonization of the gut. This will be tested in infant and adult rabbit models and in other in vitro systems. Specific outer membrane proteins will be isolated by immunoaffinity chromotography and purified, LPS-free proteins will be administered to adult rabbits by oral and parenteral routes. Antibodies in intestinal secretions and serum will be measured by highly sensitive Enzyme Linked Immunoabsorption Assays (ELISA) directed specifically to these purified proteins. Attempts will be made to evaluate their effects on resistance to challenge and interference with virulence-associated processes of V. cholerae.